Twenty trypsin-Giemsa banded metaphase cells were analyzed from 24 and 48 hour harvests of unstimulated bone marrow aspirate cell cultures. Two cells had an apparently normal male chromosome complement. One cell had a 45,XY,-3 karyotype, likely as a result of random chromosomal loss. Ten cells had a 46,XY,inv(3) (q21q26) chromosome pattern (Figures 23 & 24, demonstrating the normal and abnormal chromosome 3 respectively). There were seven hypodiploid cells, each with the inv(3)(q21q26) chromosome (Figure 25, representative karyotype). Three of these hypodiploid cells were missing one chromosome 7 with or without loss of various other chromosomes.